Overload and reverse current relay.



P. 0. KEILHOLTZ & F. E. RIUKBTTS.

OVERLGAD AND REVERSE CURRENT RELAY.

APPLICATION nun AUGS 1908.

Patented Dec. 21, 1909.

4 SHEETSSHEET 1 IN VENTORS.

A TTOR NE v.8

P. 0. KEILHOLTZ & F. B. RIGKETTS.

OVERBOAD AND REVERSE CURRENT .B-ELAY.

APPLICATION FILED AUG.5, 190B.

Patented D60. 21, 1909.

4 SHEETS-SHEET 2.

M .C P 6 4/ 8 m 7 n m V ATTORNEYCS P. U. KEILHOLTZ & F. E. RIGKETTS.

OVERLOAD AND REVERSE CURRENT RELAY.

APPLICATION FILED AUG. 5. 1908.

944,040, Patented Dec. 21, 1909.

4 SHEETBSKEBT 3.

10 Secf/qn on A-B 6/0114 r/"F 6092a? A TTORNE Y.

P. 0. KEILHOLTZ 6: F. E. RIGKETTS.

OVEBLOAD AND REVERSE CURRENT RELAY.

APPLICATION FILED AUG. 5. 1908.

Patented Dec. 21, 1909.

4 SHEETS-SHEET 4.

Shari MDIM 0 WM 0 e M Q IN VEN TOR S ATTORNEYS UNITED STATlEE ETENT OFFICE.

PIERRE O. KEILHOLTZ, 0F BALTIMORE, AND FORREST E. RICKETTS, OF DEBWOOD, MARYLAND.

OVEBLOAD AND REVERSE CUB-BENT RELAY.

Specification of Letters ratcnt.

Patented Dec. 21, 1909.

Application fled August 5, 1m. Serial No. 7,082.

To all whom it may concern:

Be it known that we, Pumas O. K1111.- non'rz and Felines-r E. Rlcnn'rrs, citizens of the United States of America, residing at the city of Baltimore, State of Maryland, and at Derwood, county of Montgomery, State of Maryland, respectively, have invented certain new and useful Improvements in Overload and Reverse Current Relays, of which the followin is a specification.

Our invention re ates to an overload and reverse current relay which is designed to afford rotection to electrical up aratus included in a circuit. It is designe primarily to operate in an alternating circuit. By protection is meant the interruption or openmg of the circuit when the electrical conditions upon the line become abnormal, such as the increase of current beyond redetermined amount or the reversal o e direction of the current. The device is not intended to open or interrupt the circuit, but itis desi ed to set in action suitable auxiliary devices which will cause such opening or interruption by pro or switches.

Referring to the t rawin s,-Figure 1 is a vertical elevation of our refly assembled and in operative position. Fig. 2 is a plan view of tie same. Fi 3 is a vertical section upon the line A- Fig. 2. Fig. 4 is a plan view of the magnets and laminated frame upon which the magnets are supported. Fig. 5 is a diagranuuatic view of the wiring. Fig. 6 is a perspective view of the slmrt'cirmuting second-aw.

Referring to the drawings,l is a casing designed to contain the device divided into two parts. a lower part in which the apparatus is located, and a cover. These two parts are provided with a cushion seat at their contacting edges to secure a dust-proof joint.

.!2-2 are 4 legs upon which the apparatus rests within the case. These logs are made integral with the case and the device is screwed down to them.

3-43 is a frame. made integral, of any suitable material, and secured to the legs 2-43.

4--4 are a pair of permanent magnets, bout as shown in Fig. 2, and located with the ends of their poles opposite each other.

5 is a yoke seemed to one of tho magnets at each cud uud ada nod to be secured in tho msls 6 J of the had 25. The posts ll--ll are Integral with (ho had 3 and are located in i the position shown in Fig. 2. The slots between the s serve to permit screws attached to t e yoke 5 to ass and to allow for vertical arhustment o the yoke.

7 is a horizontal shaft mounted at its ends in jewel bearings, one end in the stationary bearing 8, and one end in the movable hearing 9. The movable bearing consists of a screw threaded into a hole in the base of the center one of the three posts marked 6, and provided with a lock not for securing it in an adjusted position.

10 is a disk made referably of aluminum, so as to be light, and secured to the shaft 7.

11 is a screw inserted in the hub of the disk 10, and provided with a pair of nuts which may be moved back and forward upon the screw. This screw and its nuts constitute what will be called the overbalancc device of the disk, and the nuts are adjustable so as to change the amount of weight necessary to over-balance the disk.

12 is a. contact device secured to the shaft 7, and adapted to contact with another contact point 13, which is secured to the bed 3, and in circuit with a switch-operating mechanism for controlling the line. The shaft 7 is also in circuit with a source of current. The contact device 12 is located close to the axis of the shaft, that is to say, it has a very short radius so as to permit the contact poi nts to be pressed together with the greatest degree of force with any given amount of power exerted upon the disk to cause its rotation. 'Ihese parts are all mounted above the bed 3. Below the bed and secured to it upon the under side are two laminated iron frames 14 and 15, made of nunn-rous sheets of the same sha )e, which are superimposed and bolted togct ier. 'l|ie frame 14 is provided with two polo )icces, 16 and 17, and the frame 15 is provided with one pole piece 18. Upon the pole pieces 16 and 17 are wound in series two coils, l9 and .20, and on the pole piece 18 is wound a coil 21. 'lho coil 21 is in series with the coils 1% and 20. The system of cinch-o magnet is centrally arranged as to their poles, and the singc clcclro magnet has its nmguctic circuit insulated at the points 34 by non-magnetic couducting material such as brass from the twin oloctro magnets. 'lhc object for so doing is to prevent the lines of magnetic force from passing from the structure If in the polo ol the single magnet 18.

Surrounding the pole piece 18 of the electro magnet 21 is a single turn of non-magnetic material 22, having a low resistance, such as copper. This gaiece of non-magnetic material 22 consists 0 a plate of copper or brass, or other material having similar pro ertics, in the form of a U, t 0 loop of t e U being preferably rectangular and of su1table size to receive the end of the single magnet 18. The U-shaped plate has upon its upper end two flan 22 turned at right angles to the plate. e plate 22 stands vertical, opposite the ole piece 18, and In line with the face of t e pole iece, the end of the ole piece pro'ectmg rough the loop of the U. The p ate is supported by the horizontal flanges 22 upon its ends upon bosses 22 which are integral with the frame 8. 22" are slots in the horizontal flanges 22 parallel to the vertical portion of the plate and to the lane of the rotor. 22 are screws by which t e late is secured to the bosses 22. 22' is a ork on one end of one of the horizontal portions of the plate adapted to receive any suitable adjusting means. This adjustment, however, may be made by hand and the latter has not been illustrated because it is merely a means of effecting final adjustment. The plate 22, through its slots 22", is susce tible of transverse ad'ustment relative to the pole iece 18 and t e le magnet, and it me us cut off some of the lines of force of t magnet and centralize the magnet in relation to the fields of the two opposite magnets 16 and 17. Forming a part of the circuit of this non-m etic material having low resistance is an a justahle resistance 22 provided with a loop of German silver wire which may be lengthened or shortened so as to vary the resistance. The object of this adjustment is to adjust the impedance of the single coil electro magnet 21 by varyin ponent of its impedance. ponent of its impedance me. be varied by movin the non-magnetic siort-circuitin secon ary relatively to the primary coi The short-circuited secondary 22 and 22, around the pole iece 18, is to cause the magnetism of the po e piece 18 to la behind that of 16 and 17 which produces a s ifting field. The reaction of this shifting field produces rotation of the rotor. The disk 10 stands vertically between the poles of the twin magnets 19 and 20, and the single pole of the magnet 21, and rotates between them. The ovcrbalanco pin 11 is so located in the hub of the disk as to lie normull when the apparatus is not in use upon t a stop 28, from which it is raised when torque is given to the disk. As it rises, the resistance to the torque diminishes, because the resistance is maximum when the pin is in a horizontal position and zero when it is vertical. The contacts 12 and 13 are so located that they the ohmic comhe reactive comwill come together before the pin 11 reaches the vertical, and consequently the pin will always retain its power to return the disk to its primary position and open the contact. \Vhen the overbalanclng weight has been raised far enough to permit contact the minimum of resistance of the moving element becomes the moment of the contact and the full torque of the moving element is exerted in making the contact. After the contact is made the devices in the auxiliary circuit, not shown, together with the switch controlling the circuit, perform their proper functions, and the moving element rotates in a backward direction to its first position and is in readiness to operate again.

Referring to Fig. 5, the two lines on the right of the figure represent the main feeders o a circuit.

24 is a current transformer located in the main circuit and having its secondary in the circuit of the magnets 19 and 20 and 21. The binding 0st 25 is found also upon Fig. 2, and from t at binding est a circuit passes through the magnet 19, t once to ma et 20, thence to bindin post 26, thence to inding post 27, from w ich one wire asses to the coil of magnet 21 and thence to inding post 28 and thence back to the secondary of the current transformer.

29 is a potential transformer bridged across the main line, the secondary of which is in a closed circuit in which is located an ohmic resistance device 30 and a second transformer 31.

32 is the secondary coil of the second transformer located in a tertiary circuit which is connected between the posts 27 and 28. The transformer 29 reduces the voltage to a desired amount. The resistance device 30 is capable of adjustment to greatly reduce the flow of current and to secure proper phase relation between current and voltage, and the transformer 31 and 32 will still further transform the current and produce in the circuit 27, 28, 32 a regulated quantil y of current of small magnitude.

It will be observed that if just Sllfihziunl. torque is supplied to raise the adjustable weight from its stop the disk will rotate very slowly at first but increase its rotation as its moment of resistance becomes less, that is, as its adjustable weight approaches the vorticul; and if uter torque is supplied, its rate of rotation will be corr spondingly increased. This is what is known as the principle of inverse time element. The time of the operation of the disk is ulsocoutrollmi by the notion of the permanent nmgnols 4 4, between the poles of which the disk rotu-tm, and by which its rotation is rvlnrdcd. The rotating disk with its shaft ovcrlmluuco weight and contact device, ul'c the only moving parts of the apparatus, and are so losigned as to reduce their weight. to a numtill mum in order that their friction may be small. The torque of the movin element is sup lied by the magnetic field o the system of e ectro magnets which are shown.

The windings of the twin magnets are connected in series, and if an alternatin electric current is made to How througi them, the polarity of their oles will have the same cyclic variation as t ie current, that is to say, the letthand one will have, say, a north polarity, and the righthand one a south )olarity; and their polarities will rapidly a ternate. A similar current passing through the single coil magnet will also cause its pole to rapidly change its polarity. If now the circuit containing the twin electro magnets be connected in series with the single coil magnet and an alternating current he passed through them. the polarity of the poles will have a definite relation, that is to say, if the lefthund role of the twin magnet is north and the rig ithand one south, the single coil ma uct. will be north. If now reveisal takes place, the poles of the twin magncts will be south-north and the single coil magnet will be south. It now the connection of the single coil magnets be reversed, the polarity of the single coil magnet will be like the righthand pole instead of the left.- hand pole as before. If a disk free to rotate is placed in such a magnetic field, it will rotote in a definite direction, which direction can be readily reversed by changing the polarity of the single coil magnet relative] to the others. Furthermore, if the singe coil magnet is energized and the twin magnets are not energized, the disk will not rotale, and vice versa. By energizing ismeunt causing a current of electricity to flow through the windin The ma ietic effects above dcscrihed iu'e secured y a system of transformers, resistances, re-actances and connections as shown in Fig. 5.

The operation of the device may be described as follows: Assume potential on the circuit, but no power delivered from the generator to the load. Current will {low in the secondary circuit of the potential transfornu-v 29 in a definite amount. In the tertiary circuit 27. 28, 3) the current will flow through the coil of the single coil magnet and not through the coils of the twin magnets. owing to thc high reactancc of thc currcnt transformer. Consequently onlv the sin lc coil nnignct will be energized and the dis: will not operate. Let us call this curn-nt flowing from left to right. it. now. the 'c-ncrator is caused to deliver power In tu- Iinc. current will llow in the main circuit and a definite amount will llow in thc sccoudarv of the current transform-r. (all this curl-cut (lowing from right to left. The coils of thc twin mu 'ncts will be cncrim-d and the current in t in coil of thcsinglc magnct will be decreased by the amount of current flowing in the coils of the twin magnets. lhc field produced by these currents will tend to rotate the disk in the direction of the hands of a clock, which rotation is prevented hr :1 stop as before mentioned (Fig. 1). s the generator delivers more power to the line, more current will flow through the coils of the twin magnets and less will flow through the coil of the single coil magnet. We will amune that suliicient current will be delivered from the current transformer to balance the current from the potential transformer flowing in the coil of the single coil magnet. In this case the magnet is not energized and the disk will not rotate. T 0 this )oint the disk has had a decreasing torque roan a maximum, tending to rotate the disk in a direction, which is prevented by its stop, to zero torque, with no tendency to rotate. As the generator delivers more power to the line. more current will flow in the secondary of the current transformer until the direction of flow through the coil of the single coil magnet will be from ri ht to left and a torque will be sup lied to the disk to rotate it forward. depen ing 1|)0Il the amount of its unbalancing. If t ie current supplied is soliicicnt to give enough torque to overcome the inoment of resistance of the disk, it will rotate in a direction 0 posite to that of the hands of a clock. Tns result will be PlOLlllCt'll by an overload of current without dlllllllll' tion of potential. If the potential diminishes, the current balance is disturbed and the relay will operate with less current from the line. This constitutes the overload operation with loss of potential. By suitable adjustment of reactances of the rods 21 and 32 the relative rate of rotation of the disk can be controlled. It is observed that the coils of the single coil magnet and the secondary of the second transformer form a multiple connection and currents will divide between the two branches in u'oportion to their relative conductanccs. 'lhc shortcircuitcd secondary 22 afi'ords means of varying the reactive and ohmic components of the single coil nnignct and thereby alters its condnctanu'. and chan es the rclutivc How of current in this divided circuit. The reactive component is altered by changing the relative position of tin short circuitcil secondary 22 to the single coil, and thc ohmic. muuponcut is changed bv varying the resistance of the short circuilcd secondary. if thc potential remain constant and the current diminishes. becoming zero. which i the first case cited, the relay will not operate at all. If, howcvcr, the current should ohuugc its direction, as would occur if the apparatus ceased to deliver but roccivcd power. or the reverse. the rcluy will IIIN'l'llil' with loss current from the current transfornicr. This constitutes the rcvcrsc cur- 1 ill) rent operation with potential. If, under these clrrulnslmu'es, the potential should diminish, more current would be re aired from the current transformer than wit 1 full potential to cause the relay to operate. This would constitute the reverse current operation with loss of potential. It will thus be seen that our apparatus is designed to 1'0- tect electrical apparatus against all tlose accidents on the line which are likely to cause the apparatus to be destroyed by a sudden abnormal flow of current.

The apparatus is simple, durable, has but one moving element, is positive in its action, operates equally well with an abnormal flow of current from the generator or a reverse current from the line produced by a rotary transformer or from any other cause. The currents employed so balance themselves as to require a very small amount of current for the operation of the device, and the fact that. the overbalancc of the disk is eliminated when the conditions are such as to rotate the disk and close the contacts, roduces a positive and effective contact w iich secures practical and successful 0 oration.

In the structure above describe the shaftwhich carries the disk over-balance and contart is horizontal. This is the preferred form, but it will be understood that the apparatus will operate in any position in which the axis of the shaft is at an an le to the vertical. The setting of the overba ance device requires the action of gravity, which would be destroyed if the axis of the disk were vertical. The nearer the shaft is to the horizontal, the greater will be the action of gravity and the greater the sensitiveness of the device.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. In an overload and reverse current relay, the combination of an unbalanced rotor, a system of electro-magnets and an electrical contact, means for producing a reaction between the rotor and the system of elmtro-magncts proportional to the result.- ant phase composition of the current and voltage elements of the circuit to be controlled. which current and voltage elements are in multiple relation to each other.

2. In an overload and reverse current rclay. the combination of an unbalanced rotor. a system of electro-nmgnets and an electrical contact, means for producing a reaction between he rotor and the system of ch-rtro-magiwts proportional to the resultant phase mnu msition of the current and voltage elements of the circuit to he controlled: which consists of a derived current and voltage circuit encircling the nmgnets and responding to variations of electrical conditions on the working circuit.

3. in an overhaul and reverse current relay, the mnnhinatiou of a current transformer in the main line, a pair of twin electro magnets in series with the secondary of the transformer, a single electro ma et having its pole set opposite the poles o the twin magnets and in series with the twin magnets and the secondary of the current transformer, a potential transformer across the main line the secondary of which is in a closed circuit containing an ohmic resistance device, and a. second transformer the secondary of which is in shunt relation to the circuit of the current transformer and including the single electro magnet coil, a rotor mounted upon a shaft set at an an 10 to the vertical and arranged to rotate in t: e fields of the twin and sin le ma ets, the rotor being unbalanced, and an e ectrical conta t adapted to be closed by the rotation of the rotor.

4. In an overload and reverse current relay, the combination of a current transformer in the main line, a pair of twin electro magnets in series with the secondary of the transformer, a single electro magnet having its pole in magnetic relation to the poles of the twin magnets and in series with the twin ma nets and the secondary of the current trans ormer,a potential transformer across the mainline the secondar of which is in shunt relation to the circuito the current transformer and including the single electromagnet coil, a rotor mounted upon a shaft set at an angle to the vertical and arranged to rotate in the magnetic field of the stem of magnets, the rotor being unbalanc and an electrical contact adapted to be closed by the rotation of the rotor.

5. In an overload and reverse current rclay, the combination of a current transformer in the main line, a pair of twin electro magnets in series with the secondar of the transformer, a single clcctro magnet aving its pole in magnetic relation to the poles of the twin magnets and in series with the twin magnets and the secondary of the current transformer. a potential transformer acrt ss the main line the secondary of which is inshunt relation to the circuit. of the current transformer and including the single elw'tro-umgnet coil. a rotor mounted upon a shaft set at :in angle to the vertical and arranged to rotate in the magnetic field of the system of magnets, the rotor being unbalanced. and an electrical contact adapted to he closed by the rotation of the rotor, the pole of the single magnet being in such magnetic relation to the poles of the twin magnet as will induce currents in the rotor which will react upon the system of elect ro nuigm-ts and cause rotation of the ruler.

It. In an overload and reverse current rcluy, lln' combination of an unlmhnwml rotor mounted between the poles of a pair of twin magnets and the pole. of an oppositely dis- Ill) iltl

posed single Ina met, and an electrical contact adapted to closed when the rotor is given a desired direction of rotation, the magnets being in series and in circuit with the secondary of a current transformer in the main line, and a secondary circuit also including the coil of the single ma net and the secondary coil of a potentiiii transformer.

7. In an overload and reverse current relay the combination of an unbalanced rotor mounted between the poles of a pair of twin magnets and the pole of an o ipositel disposed single uuvmet. and an e cctrica contact adapted to he closed when the rotor is given a desired direction of rotation, the magnets being in series and in circuit with the secondary of a current transformer in the main line, and a secondary circuit also including the coil of the single magnet and the secondary coil of a potential transformer, and means for varying the impedance of the secondary circuit.

8. In an overload and reverse current relay the combination of an unbalanced rotor mounted between the poles of a pair of twin magnets and the pole of an oppositely disposed single magnet, and an electrical contact adapted to be closed when the rotor is given a desired direction of rotation, the

magnets being in series and in circuit with the secondary of a current transformer in the main line, and a secondary circuit also including the coil of the single magnet and the secoudar coil of a potential transformer, and means or varying the impedance of the single coil magnet.

9. In an overload and reverse current rclay, the combination of an unbalanced rotor mounted between the poles of a pair of twin magnets and the pole of an oppositely dis posed single ma net and an electrical contact adapted to e closed when the rotor is given a desired direction of rotation, the magnets being in series and in circuit with the secondary of a current transformer in the main line, and a secondary circuit also in cluding the coil of the single magnet and the secondary coil of a transformer, the primary of which is included in a circuit which also includes an ohmic resistance and the secondary of a potential transformer.

Signed by as at Baltimore, Md, this 3rd day of J nly 1908.

PIERRE O. KEILHOLTZ. FORREST E. RICKETTS.

Witnesses:

EDWARD L. BASH, B. Sonaoe'rnn. 

